1. Technical Field
The present invention relates to an MEMS component.
2. Description of the Related Art
Micro electro mechanical systems (MEMS) are a technology of manufacturing an ultra-fine machine structure, such as a ultra-high density integrated circuit, an inertial sensor, a pressure sensor, an oscillator, or the like, by machining silicon, crystal, glass, or the like. The MEMS component has a precision of micrometer ( 1/1,000,000 meter) or less and structurally uses a semiconductor micro manufacturing technology that repeats processes, such as deposition, etching, or the like, thereby mass-producing micro products at low costs.
An inertial sensor, one of the MEMS components, has been used in various fields, for example, the military, such as an artificial satellite, a missile, an unmanned aircraft, or the like, vehicles, such as an air bag, electronic stability control (ESC), a black box for a vehicle, or the like, hand shaking prevention of a camcorder, motion sensing of a mobile phone or a game machine, navigation, or the like.
The inertial sensor generally adopts a configuration in which a mass body is bonded to a flexible substrate such as a membrane, or the like, so as to measure acceleration and angular velocity. Through the configuration, the inertial sensor may calculate the acceleration by measuring inertial force applied to the mass body and may calculate the angular velocity by measuring Coriolis force applied to the mass body.
In detail, a process of measuring the acceleration and the angular velocity by using the inertial sensor will be described in detail below. First, the acceleration may be obtained by Newton's law of motion “F=ma”, where “F” represents inertial force applied to the mass body, “m” represents a mass of the mass body, and “a” is acceleration to be measured. Therefore, the acceleration a may be obtained by sensing the inertial force F applied to the mass body and dividing the measured inertial force F by the mass m of the mass body that is a predetermined value. Meanwhile, the angular velocity may be obtained by Coriolis force “F=2mΩ·v”, where “F” represents the Coriolis force applied to the mass body, “m” represents the mass of the mass body, “Ω” represents the angular velocity to be measured, and “v” represents the motion velocity of the mass body. Among others, since the motion velocity v of the mass body and the mass m of the mass body are values that are known in advance, the angular velocity Ω may be obtained by sensing the Coriolis force (F) applied to the mass body.
However, the inertial sensor according to the prior art is influenced by disturbance or noise occurring from external environment or interference from surrounding sensors and as a result, sensitivity thereof may be degraded.
In addition, in the inertial sensor according to the prior art, when an excessive force is applied to the mass body, supporting parts of the mass body, for example, the membrane, or the like, may be damaged. In particular, when the inertial sensor crashes to the ground due to free falling, a very large force is applied to the mass body, such that it is highly likely to damage the supporting part of the mass body.
In addition, in the inertial sensor according to the prior art, so as to protect the mass body, a cap needs to be bonded to a bottom surface of a post so as to surround the mass body and an adhesive bonding the post to the cap may be permeated into the post. When the adhesive is permeated into the post, a space between the mass body and the cap is reduced, thereby deteriorating dynamic characteristics of the inertial sensor. In addition, when an amount of the adhesive permeating into the post is increased, the adhesive is directly bonded to the mass body, thereby causing defects of the inertial sensor.
Although the above-mentioned problems are described based on the inertial sensor, the above-mentioned problems may also occur in the pressure sensor, the oscillator, or the like, having a very similar structure to the inertial sensor among the MEMS components.